Gamma-Rays from Nucleosynthesis Ejecta

Gamma-ray lines from radioactive decay of unstable isotopes produced in massive-star and supernova nucleosynthesis have been measured with INTEGRAL over the past ten years, complementing the earlier COMPTEL survey. Al-26 has become a tool to study specific source regions, such as massive-star groups and associations in nearby regions which can be discriminated from the galactic-plane background, and the inner Galaxy where Doppler shifted lines add to the astronomical information. Recent findings are that superbubbles show a remarkable asymmetry, on average, in the spiral arms of our galaxy. Fe-60 is co-produced by the sources of Al-26, and the isotopic ratio from their nucleosynthesis encodes stellar-structure information. Annihilation gamma-rays from positrons in interstellar space show a puzzling bright and extended source region central to our Galaxy, but also may be partly related to nucleosynthesis. Ni-56 and Ti-44 isotope gamma-rays have been used to constrain supernova explosion mechanisms. Here we summarize latest results using the accumulated multi-year database of observations, and discuss their astrophysical interpretations. We also add a comparison of isotopic ratios between the ISM of the current Galaxy and the solar vicinity at solar-system formation time.